Delhi has started with the second edition of its previously much-talked about Odd Even rule. The Odd-Even rule was implemented after the air in the national capital became too dangerous to breath in. All the media houses shouted few words all the time : “high PM levels; PM 10 and PM 2.5 levels cross the safe limit; air in Delhi too harmful”.

So how exactly does the PM levels harm our body? Infact, lets start with what exactly is PM?

Particulate matter (or PM) is the term used for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye.

What is PM 10 and PM 2.5?

PM 10 is particulate matter 10 micrometers or less in diameter, PM2.5 is particulate matter 2.5 micrometers or less in diameter. PM2.5 is generally described as fine particles. By way of comparison, a human hair is about 100 micrometers, so roughly 40 fine particles could be placed on its width

Fine particulate matter (PM2.5) is an air pollutant that is a concern for people’s health when levels in air are high. PM2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated. Outdoor PM2.5 levels are most likely to be elevated on days with little or no wind or air mixing. The New York State Departments of Health (DOH) and Environmental Conservation (DEC) alert the public by issuing a PM2.5 Health Advisory when PM2.5 concentrations in outdoor air are expected to be unhealthy for sensitive groups.

So where does the fine particulate matter come from?

There are outdoor and indoor sources of fine particles. Outside, fine particles primarily come from car, truck, bus and off-road vehicle (e.g., construction equipment, snowmobile, locomotive) exhausts, other operations that involve the burning of fuels such as wood, heating oil or coal and natural sources such as forest and grass fires. Fine particles also form from the reaction of gases or droplets in the atmosphere from sources such as power plants. These chemical reactions can occur miles from the original source of the emissions. PM2.5 is also produced by common indoor activities. Some indoor sources of fine particles are tobacco smoke, cooking (e.g., frying, sautéing, and broiling), burning candles or oil lamps, and operating fireplaces and fuel-burning space heaters (e.g., kerosene heaters).

increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing.

Apart from health effects, presence of PM also affects the visibility around. It produces haze, which creates problems for people behind the wheels.

FICCI Research and Analysis Centre (FRAC), which a Environment Monitoring and Food & Beverage testing lab is associated with the Government of NCT in carrying out Ambient Air Quality Monitoring for this edition of Odd Even Rule!